U.S. President Barack Obama on Monday called for a coordinated, urgent action on climate change, declaring that the United States bore part of the responsibility for what he termed the most serious challenge of the century.

“Climate change is no longer some far-off problem; it is happening here, it is happening now,” Obama said at an international conference in Alaska, the New York Times reported. "We are not moving fast enough. None of the nations represented here are moving fast enough."

He also acknowledged that the U.S. "recognizes our role in creating this problem and embraces our role in solving it."

Obama took the unusually blunt stance at the opening of the three-day Global Leadership in the Arctic: Cooperation, Innovation, Engagement and Resilience, or GLACIER. He also underscored the need for securing a strong replacement for the greenhouse gas reduction targets set out in the 1997 Kyoto Protocol, which the U.S. has refused to ratify.

Last week, Obama had stressed the importance of immediate solutions to help the country weather the effects of climate change. "As I'll talk about next week, when I visit Alaska, making our communities more resilient is going to be increasingly important, because we're going to see more extreme weather events as the result of climate change -- deeper droughts, deadlier wildfires, stronger storms," Obama said in New Orleans, while commemorating the 10th anniversary of Hurricane Katrina.

Early this year, Obama promised to slash U.S. emissions levels by between 26 percent and 28 percent by 2025. He also pushed for other nations, including the world’s largest greenhouse gas emitter, China, to make similar pledges.

Obama's efforts come ahead of a major international climate conference hosted by the United Nations, scheduled to be held in Paris in December. The summit will come six years after a conference in Copenhagen, Denmark, marked the first time the international community acknowledged the urgency of reducing emissions. However, those negotiations later broke down, resulting only in a non-binding accord that has been criticized for failing to set solid targets.

“This year, in Paris,” Obama said in Alaska, “has to be the year that the world finally reaches an agreement to protect the one planet that we’ve got while we still can.”

"We're proving that there doesn't have to be conflict between a sound environment and strong economic growth," he added. "Let's be honest: This has always been one of the arguments against action. We don't want our lifestyles disrupted. Which is ironic, because few things will disrupt our lives as profoundly as climate change."

Scientists have warned that the majority of the world’s untapped fossil fuels must stay in the ground in order to avoid a catastrophic rise in temperature that would result in rising sea levels, widespread droughts and intensifying storms.

Obama’s speech was chosen to highlight communities in Alaska where climate change was already beginning to have conspicuous effects. Over the course of his trip, the president is set to hike Exit Glacier in Alaska’s Kenai Mountains, which is retreating due to rising temperatures. He will also record a segment with wilderness survivalist Bear Grylls for his NBC program “Running Wild With Bear Grylls,” as well as meet local fishermen and travel to the city of Kotzebue in Alaska's Northwest Arctic Borough where coastal erosion is threatening villages.